Faster than Light
Superluminal Phenomena, Communication, Space Drives, Consequences, and Implications No discussion of futuristic space travel is complete without a discussion of the speed of light. It is a barrier, that as far as we know, is unbreakable. This does not mean there has been a lack of efforts to find a way around it. Also, it is theoretically possible for faster than light particles to exist, however, as of yet, there is no evidence of their existence. The speed of light is the speed at which a massless object must travel. It is also the limit for communication and information transfer. This information includes, at minimum, the parameters of force fields and spacetime, and changes to these propagate at the speed of light. This radiation serves to “communicate” the physical “information” regarding the state of the universe. There are some phenomena that can move faster than light, however, no mass or information is transmitted as fast. Very far celestial objects, if treated as revolving around an Earth-bound reference frame, appear to cover vast distances far faster than light. Long shadows and the light spots at the ends of beams can travel across surfaces faster than light, as can the intersection points between them. The fields emanating from a moving object or the combined speed of two converging objects can also be greater than c. The phase and group velocities for electromagnetic radiation can exceed the speed of light, however, intricacies of wave propagation mean that no information is transferred faster than light. An oft cited example for traveling faster than light is quantum entanglement. This is when a change in state of one particle is instantly transmitted and adopted by an entangled particle no matter how far away. Due to the quirks of quantum mechanics, this does not mean information can travel faster than light. When the one particle is observed, it randomly collapses into a state, and this is the same state the other particle adopts. The transmitter can’t “control” the sending state, and a receiving observer would not be able to distinguish a signal from random noise. Since the universe is expanding, and the rate of expansion is proportional to distance, objects more than a certain distance apart are travelling away from each other faster than light speed. This does not violate relativity because spacetime itself is what is moving, and it is perfectly free to do so. This concept has been applied to the concept of warp drives, where the local spacetime is moved through the rest of the universe at a speed greater than c. It also applies to wormholes, stargates, hyperdrives, and Krasnikov tubes, all of which create shortcuts and bypasses in spacetime. A concentrated mass or energy can spin and produce frame dragging effects with similar results. The rotational inertial forces will create additional strange effects. Essentially, nothing can travel faster than light in its own reference frame, but may appear to exceed c outside of it. Unless Mach’s principle is true, it means we may be able to achieve practical superluminal travel. One last loophole through which we could exceed light speed would be to produce particles with imaginary masses. These would automatically be tachyons, or particles that must travel faster than light. They would gain mass as they slowed down, and would never go as slow as light. Also, a negative mass coupled to a positive mass could exceed light speed. The positive mass would constantly pull on the negative mass, and the negative mass would constantly push the positive mass away, driving a runaway acceleration. When one calculates momentum and energy in this case, both are conserved and remain less than infinity because of the negative mass reducing the total mass. All faster than light schemes would result in time distortion effects. If an object travels at high subluminal speeds, less time will pass for the object than for an outside observer. Warps, wormholes, and stationary and spinning compact spacetimes, can all lead to similar effects for outside observers, where time goes by slower or faster for travelers. Tachyons and superluminal objects will appear to travel back in time in certain situations. Science fiction writers have come up with many ways to sneak around the light barrier. They can be grouped in 3 ways. They can be discontinuous drives, which involve traveling in steps, called jumps, to instantaneously travel from point to point along the way. Continuous drives have the spaceship travel along a path that serves as a highway, bypass, or shortcut from point A to B. Finally, they can involve changing parameters of the universe to facilitate superluminal travel. Faster than light travel would allow humanity to truly explore the universe. We would not be confined to our local galactic supercluster, and would be able to cross the vast voids of space. We could also use these techniques to create various time machines, and perhaps truly rewrite the history books and our future.